Internet protocol radio access network (IP RAN) is an existing main solution in mobile carrier network technology. Based on a design concept of flexible IP communication, a bearer path is planed by means of static routing manually configured by a network administrator, and a received signal quality is guaranteed by incorporating traffic engineering (TE) channel technology with hierarchical Quality of Service (QoS). In the IP RAN solution, considering a high reliability of telecommunication service required by telecommunication standard, a virtual private network (VPN) (including a layer 2 VPN and a layer 3 VPN, i.e., L2VPN and L3VPN) is commonly carried by a public-network TE tunnel. The IP RAN is a network converged layer by layer, and a network architecture thereof includes an access layer, a convergence layer and a kernel layer.
In multi-protocol label switch traffic engineering (MPLS TE), advantages of multi-protocol label switch (MPLS) and the TE are combined to implement a dynamical adjustment of network bandwidth resources and an optimization of the distribution, thus solving the network congestion. In the MPLS TE, a topology calculation is performed based on the link status, and a LSP is created. In the IP RAN, the bandwidth of the access layer is different from that of the convergence layer, and the service planning carrying capacity of the access layer is different from that the convergence layer. A convergence layer may provide a service to each access layer, and the access layer may not carry a traffic redundancy. Thus, in the IP RAN, the LSP may be calculated to avoid passing through other access areas of the access layer. In addition, another requirement of the IP RAN is to provide a main-standby path protection. In a desirable condition, the main and standby LSPs are completely separated, i.e., no common channel exists between the main and the standby LSPs. The complete separation of the main and standby LSPs includes the separation of the links, and the separation of nodes. In this way, it may be guaranteed that the status of standby LSP may not be affected by a failure at any link or node in the main LSP.
At present, the LSP is affected by explicit paths of the TE. It may be guaranteed that the LSP may not pass the access layer by allocating aggregation nodes to connect with the node and link directing to the convergence layer. Alternatively, a key node, where the main and the standby paths may intersect, may be allocated to the main path or the standby path, to ensure the separation of the main and standby LSPs. Thus, by affecting the LSP by the explicit paths of the TE, the LSP may be avoided from passing the access layer, and the main and the standby paths may be separated. However, the explicit paths of the TE need a manual intervention on the attribute description of the TE channel, and thus it is difficult to implement an automatic calculation.